Starter provided with electromagnetic solenoid integrating rush current suppression function

Abstract

An electromagnetic solenoid that controls a motor current of a starter includes: a first switch including a pair of first fixed contacts and a first movable contact, intermitting the motor current; a suppression resistor that suppresses the motor current; a second switch including a pair of second fixed contacts and a second movable contact, making a short circuit path to bypass the suppression resistor; a regulation member being driven by a sub solenoid, regulating the second switch being closed and releasing the second switch from being regulated after predetermined time elapses when a plunger is pulled by a main electromagnet. The regulation member is disposed between a regulated position and a released position to regulate the second switch.

What is claimed is: 
     
       1. A starter for starting an engine mounted on a vehicle, comprising:
 a motor that generates rotational force by being energized, the motor rotating about a rotational axis thereof; 
 a pinion that transmits the rotational force of the motor to a ring gear of the engine when the pinion engages with the ring gear; and 
 an electromagnetic solenoid fixed to a starter housing to be in parallel with the motor such that the rotational axis of the motor and an axial direction being a longitudinal direction of the electromagnetic solenoid are parallel, wherein
 the electromagnetic solenoid includes: 
 a pair of first fixed contacts disposed at an activation circuit of the motor; 
 a first movable contact facing the pair of first fixed contacts, being movable in the axial direction to open and close the pair of first fixed contacts, the pair of first fixed contacts being closed when the first movable contact contacts with the pair of first fixed contacts and the first fixed contacts being opened when the first movable contact is separated from the pair of first fixed contacts; 
 a first switch that intermittently cuts off a current supplied to the motor in response to the first movable contact opening and closing the pair of first fixed contacts, the first switch being opened when the first movable contact opens the pair of first fixed contacts and being closed when the first movable contact closes the pair of first fixed contacts; 
 a suppression resistor connected to the activation circuit to be in series to the first switch, suppressing rush current flowing into the activation circuit when the first switch is closed; 
 a pair of second fixed contacts disposed at the activation circuit, bypassing the suppression resistor; 
 a second movable contact facing the pair of second fixed contacts, being movable in the axial direction to open and close the pair of second fixed contacts, the pair of second fixed contacts being closed when the second movable contact contacts with the pair of second fixed contacts and the pair of second fixed contacts being opened when the second movable contact is separated from the pair of second fixed contacts; 
 a second switch that short-circuits the suppression resistor to make a short circuit path when the second movable contact closes the pair of second fixed contacts, the second switch releasing the short circuit path when the second movable contact opens the pair of second fixed contacts, the second switch being opened when the second movable contact opens the pair of second fixed contacts and being closed when the second movable contact closes the pair of second fixed contacts; 
 a main solenoid including a main electromagnet when being energized and a plunger being pulled by the main electromagnet to move in the axial direction, wherein the main solenoid pushes the pinion out towards the ring gear in response to the plunger moving in the axial direction and drives the first movable contact and the second movable contact towards the pair of first fixed contacts and the pair of second fixed contacts respectively; 
 a regulation member disposed to be movable between a regulated position and a released position, the regulated position regulating movement of the second movable contact not to contact with the pair of second fixed contacts when the second switch is being closed, the released position releasing movement of the second movable contact so as to allow the second movable contact to contact with the pair of second fixed contacts; and 
 a sub solenoid forming a sub electromagnet when being energized, driving the regulation member to be at the regulated position when the sub electromagnet is ON and releasing the regulation member to be at the released position when the sub electromagnet is OFF, wherein 
 the sub solenoid is configured to control the sub electromagnet to be ON and OFF such that the regulation member is driven to be at the regulated position before the second switch is closed when the main solenoid starts to operate, so as to regulate the movement of the second movable contact and the regulation member is released to be at the released position when a predetermined time elapses after the plunger is pulled by the main electromagnet, so as to release the movement of the second movable contact. 
 
 
     
     
       2. The starter according to  claim 1 , wherein
 the sub solenoid includes a small plunger being pulled by the sub electromagnet thereby allowing the small plunger to move in the axial direction; 
 the regulation member is disposed to be movable together with the small plunger between the regulated position and the released position; and 
 the small plunger is pulled by the sub electromagnet before the second movable contact contacts with the regulation member, when the regulation member is driven to be at the regulated position. 
 
     
     
       3. The starter according to  claim 1 , wherein
 the first switch and the second switch is configured such that when the first moveable contact and the second movable contact are separated from the pair of first fixed contacts and the pair of second fixed contacts respectively in response to an operation stop of the main solenoid, the second movable contact is separated from the pair of first fixed contacts before the first movable contact is separated from the pair of second fixed contacts. 
 
     
     
       4. The starter according to  claim 1 , wherein
 the electromagnetic solenoid includes a frame having a cylindrical shape and serving as a magnetic circuit of the main solenoid and a switch cover that is fixed to the frame to cover an opening of the frame; 
 a first connection terminal connected to a battery side of the activation circuit and a second connection terminal connected to a motor side of the activation circuit are fixed to the switch cover; 
 a B-fixed contact connected to the first connection terminal, an M-fixed contact connected to the second connection terminal, a B-intermediate fixed contact being paired with the B-fixed contact and an M-intermediate fixed contact being paired with the M-fixed contact which are arranged inside the switch cover; and 
 either one of the first fixed contact or the second fixed contact is constituted by the B-fixed contact and the B-intermediate fixed contact and the other one of the first fixed contact or the second fixed contact is constituted by the M-fixed contact and the M-intermediate fixed contact; and the B-intermediate fixed contact and the M-intermediate fixed contact are electrically connected from each other. 
 
     
     
       5. The starter according to  claim 4 , wherein
 the B-intermediate fixed contact and the M-intermediate fixed contact are integrated to be a common intermediate fixed contact. 
 
     
     
       6. The starter according to  claim 4 , wherein
 one end of the suppression resistor is connected to the B-fixed contact and the other end of the suppression resistor is connected to the B-intermediate fixed contact or the common intermediate fixed contact. 
 
     
     
       7. The starter according to  claim 1 , wherein
 the starter includes a control circuit that controls an operating time of the sub solenoid. 
 
     
     
       8. The starter according to  claim 7 , wherein
 the control circuit is integrated to the electromagnetic solenoid. 
 
     
     
       9. The starter according to  claim 7 , wherein
 the starter includes a conduction terminal connected to the battery via a harness, the conduction terminal is a single terminal at which the harness is connected, and a wiring from the conduction terminal is branched to connect the main solenoid, the sub solenoid and the control circuit. 
 
     
     
       10. The starter according to  claim 4 , wherein
 the sub solenoid is disposed inside the switch cover; 
 the sub solenoid includes a sub coil that forms the sub electromagnet when being energized; and 
 a negative side of the sub coil is connected to the second connection terminal to be grounded via the motor. 
 
     
     
       11. The starter according to  claim 10 , wherein
 the motor includes a commutator and a brush, the motor is configured such that contact between the commutator and the brush becomes unstable before the motor loses a required performance for restarting the engine due to wear of the brush sliding on an outer periphery of the commutator; and 
 the sub solenoid is configured such that a driving voltage applied to the sub coil is decreased when the contact between the commutator and the brush becomes unstable, whereby the sub solenoid cannot obtain required regulation force to regulate the movement of the second movable contact by the regulation member. 
 
     
     
       12. The starter according to  claim 11 , wherein
 the motor is configured such that a brush pigtail of the brush is hooked at a brush holder that holds the brush before the brush wears to reach an operating life thereof, whereby the contact between the commutator and the brush becomes unstable. 
 
     
     
       13. The starter according to  claim 7 , wherein
 the second connection terminal is formed by a plate-shaped member being made of metal, one end side of the plate-shape member forms the M-fixed contact inside the switch cover, the other end side of the plate-shape member is protruded in a radial direction being perpendicular to the axial direction from a surface of the switch cover to to be inserted into the motor and electrically connected to the brush inside the motor; and 
 the control circuit is disposed in the switch cover to be at an anti-movable contact side in the axial direction with respect to the M-fixed contact. 
 
     
     
       14. An engine starting unit including the starter according to  claim 1 , wherein
 the engine starting unit includes an operation determining unit that determines whether or not the sub solenoid operates properly when the engine is restarted from an idle stop condition; and 
 the operation determining unit detects an occurrence of a voltage drop caused by a rush current in response to contacts of the first and second switches coming into contact to close the respective switches and, determines that the sub solenoid has operated properly when the operation determining unit detects that the voltage drop occurs twice and determines that the sub solenoid has not operated properly when the operation determining unit does not detect a second voltage drop after occurrence of a first voltage drop. 
 
     
     
       15. An engine starting unit including the starter according to  claim 2 , wherein
 the engine starting unit includes an operation determining unit that determines whether or not the sub solenoid operates properly when the engine is restarted from an idle stop condition; 
 the operation determining unit detects an occurrence of a voltage drop caused by a rush current in response to contacts of the first and second switches coming into contact to close the respective switches and, determines that the sub solenoid has operated properly when the operation determining unit detects that the voltage drop occurs twice and determines that the sub solenoid has not operated properly when the operation determining unit does not detect a second voltage drop after occurrence of a first voltage drop. 
 
     
     
       16. An engine starting unit including the starter according to  claim 3 , wherein
 the engine starting unit includes an operation determining unit that determines whether or not the sub solenoid operates properly when the engine is restarted from an idle stop condition; 
 the operation determining unit detects an occurrence of a voltage drop caused by a rush current in response to contacts of the first and second switches coming into contact to close the respective switches and, determines that the sub solenoid has operated properly when the operation determining unit detects that the voltage drop occurs twice and determines that the sub solenoid has not operated properly when the operation determining unit does not detect a second voltage drop after occurrence of a first voltage drop.